Erythema marginatum is a rare skin rash that spreads on the trunk and limbs. The rash is round, with a pale-pink center, surrounded by a slightly raised red outline. The rash can appear in rings or have less regular, larger, or elongated shapes.

The rash isn’t a disease in itself. Rather, it can be a symptom of an underlying condition, such as:

There are several other kinds of erythema rashes besides erythema marginatum. These include:

  • erythema migrans, which tends to stay in one place on the body
  • erythema multiforme lesions, which can spread over the body and appear as raised, crusty patches
  • erythema annulare centrifugum, which can be itchy and scaly, and may appear on the face

These rashes are only connected by the term “erythema”, which means “red.” They each have distinctive characteristics and causes that are otherwise unrelated.

Read on to learn more about erythema marginatum.

The erythema marginatum rash can look like a faint pattern on your skin with a pinkish center, and a flat or slightly raised red border. The overall shape can be regular rings or semicircles, or less regular shapes with wavy margins.

Erythema marginatum fades in and out over time. It only for hours, or for days or longer. The rash isn’t itchy or painful, and it may not be noticeable on darker skin tones.

Erythema marginatum appears mostly on the trunk and limbs. It doesn’t usually appear on the face.

There are several conditions that can cause erythema marginatum rash.

Rheumatic fever

The most common cause of erythema marginatum is rheumatic fever. It’s present in about of people with the disease. Other symptoms are:

Rheumatic fever is a complication from strep throat that isn’t adequately treated with antibiotics. It can lead to serious heart damage. The disease is very rare in the United States now, with an occurrence of children. Rheumatic fever and rheumatic heart disease (RHD) are in underdeveloped countries. There are an estimated cases of RHD worldwide.

Hereditary angioedema

Erythema marginatum may be an early sign of hereditary angioedema. The rash occurs in about of children with a type of hereditary angioedema referred to as C1-INH-HAE, including newborns.

This rare inherited disease occurs in about . Symptoms often don’t appear until after puberty.

The erythema marginatum rash can be important as a warning of an upcoming attack. the rash is misdiagnosed as hives, delaying testing for angioedema.

Other symptoms include:

  • cramps
  • nausea
  • swelling of the face, hands, arms, and legs
  • gastrointestinal problems
  • irritability
  • fatigue

Lyme disease

Rarely, erythema marginatum can be one of the skin symptoms of Lyme disease, though erythema migrans is more commonly seen with this condition.

Lyme is an often-debilitating disease transmitted by Borrelia burgdorferi bacteria via blacklegged deer ticks. It’s difficult to diagnose because its wide range of symptoms mimic those of many diseases.

Symptoms include:

  • fatigue
  • achy, stiff, or swollen joints
  • headache, fever, dizziness, and other flu-like symptoms
  • night sweats and sleep disturbances
  • cognitive decline
  • neurological problems

Allergies

Adverse reactions to certain drugs can produce an erythema marginatum rash. For example, the combination antibiotic amoxicillin-clavulanate (Augmentin) can erythema marginatum.

If you or your child has a rash that looks like erythema marginatum, see a doctor. The rash is not dangerous in itself, but could indicate a serious underlying condition.

Your doctor will ask about your medical history, medications you are taking, and other symptoms.

If you’ve recently had strep throat, your doctor may order blood tests to look for markers of rheumatic fever. They may also do tests to check for heart damage. There is no one test to diagnose rheumatic fever.

Your doctor may also order blood tests if inherited angioedema is suspected to check for decreased C1 inhibitor, which is a sign of the condition.

Lyme is often diagnosed on the basis of symptoms and a blood test.

There’s no treatment for erythema marginatum. The rash fades on its own. You may need to be treated for an underlying condition responsible for the rash.

Rheumatic fever is treated with:

  • antibiotics for infection
  • salicylates for arthritic symptoms
  • corticosteroids for heart involvement

Inherited angioedema is treated with C1 esterase inhibitor (Cinryze) or icatibant (Firazyr).

Lyme is treated with antibiotics.

The illnesses that commonly cause erythema marginatum are rare in developed countries, and therefore this rash isn’t often seen in the United States. Other, similar rashes are more common and can be confused with erythema marginatum. It’s important to see your doctor for an accurate diagnosis.

The erythema marginatum rash fades out on its own over time, sometimes in hours. It can be a symptom of various underlying conditions, but usually rheumatic fever. If you have inherited angioedema, the rash may return as a forewarning of an attack.